Office



1 UNITED STATES PATENT OFFICE.

CARL OSCAR MULLEEQOF BASLE, SVITZERLAND, ASSIGNOR TO BASLE CHEMICALYVORKS BINDSCI-IEDLER, OF SAME PLACE.

RHODAMIN DYE.

SPECIFICATION forming part of Letters Patent No. 576,222, dated February2, 1897. 7

Application fil d June 30, 1896. Serial No. 597,643. (Specimens)Patented in France March 6, 1895,11'0. 245,593, and in England March 8,1895,15l0. 4,985.

To all whom it may concern:

Be it known that I, CARL OSCAR MiiLLER, chemist, a subject of theEmperor of Germany, residing at Basle, Switzerland, have inventedcertain Improvements in the Manufacture of Rhodamin Dyes, (which havebeen patented in France by Letters Patent No. 245, 593, dated March 6,1895, and in England by Letters Patent No. 4,985, dated March 8, 1895,)of which the followingis a clear and complete specification.

The new dialkylamidooxybenzoyl-benzoic acids,which are fully describedin another application, Serial No. 597,642,- filed June 30, 1896, forLetters Patent ofthe inventor, and which are obtained by thecondensation of one molecule anhydrous phtalic acid with one moleculedialkylmetaamidophenol, can easily be converted into symmetrical andunsymmetrical rhodamin dyes by their condensation with the alkylderivatives of motaimidophe 1101 in presence of a convenient agent ofcondensation, as, for instance, concentrated sulfuric acid. Theunsymmetrical rhodamin dyes thus obtained are new articles ofmanufacture and cannot be produced by any other of the hitherto-knownprocesses for the manufacture of rhodamin dyes bymeans of anhydrousphtalic acid and metaamidophenols.

Example I: Fourteen kilograms dimethylamidooxybenzoyl-benzoic acid andten kilograms diethylmetaamidophenol are dissolved in seventy kilogramssulfuric acid of about ninety-eight per cent. (11 The solution is heatedto about centigrade until a test gives a clear solution in water. Thenit is poured into about eight hundred liters of water and boiled. Thedyestuff then is precipitated by an addition of sea-salt. Its

base is dissolved in diluted hydrochloric acid, from which the dyestuifis crystallized in the form of the h ydrochlorate. The base of thisunsymmetrical dimethyldiethyl rhodamin dye has probably the followingconstitutional formula:

amidooXybenzoyl-benzoic acid with dimethylmetaamidophenol.

Example II: Twenty kilograms dimethylamidooxybenzoyl -benzoic acid andfifteen kilograms monoethylmetaamidophenol are dissolved in a mixture offifty kilograms water and two hundred kilograms sulfuric acid,(monohydrate) The Whole is heated from to centigrade, and when a testgives a clear solution in warm Water it is poured into about sevenhundred liters water. The dyestufi is precipitated by sea-salt filteredand purified by recrystallization from hot water acidnlated by sulfuricacid. It dyes wool, silk, and, with tannin, mordanted cotton in redtints.

The sulfate of the dyestufi constitutes green needles soluble in waterand in alcohol. Its alcoholic solution has a greenish yellowfluorescence.

The dyestufi' base is soluble in alcohol,ether, and benzene. Sulfuricacid (monohydrate) and hydrochloric acid dissolve the coloringmatterwith a yellow color.

WVhat I claim as my invention, and wish to secure by Letters Patent, is

1. The improvement in the manufacture of rhodamin dyes, consisting inthe production of a coloring-matter by the condensation of one moleculeof a dialkylamidooxybenzoylbenzoic acid derived from one moleculeanhydrous phtalic acid and one molecule of a dialkylmetaamidophenol,with one molecule of an alkyl derivative of metaamidophenol, asdescribed.

2. The-improvement in the man ufacturc of rhodamin dyes, consisting inthe production of a coloring-matter by the condensation of one moleculeof a dialkylamidooxybenzoylbenzoic acid derived from one moleculeanhydrous phtalic acid and one molecule of a CARL OSCAR MULLER.

\Vitnesses EMIL PARAVICINI, AMAND BITTER.

